Abstract: An apparatus for switching and controlling the intensity of a laser beam directed toward a beam detect sensor for an image forming device. A printing power reference signal and a beam detect power reference signal is selectively connected to a laser driver through a first switch. A printing power reference holding capacitor and a beam detect power reference holding capacitor is selectively connected to the laser driver through a second switch that is controlled in tandem with the first switch. During each scan cycle, the output laser power is monitored and used to adjust one of the two holding capacitors based such that both the printing power and the beam detect power have a controlled reference.

Abstract: An apparatus for switching and controlling the intensity of a laser beam directed toward a beam detect sensor for an image forming device. A printing power reference signal and a beam detect power reference signal is selectively connected to a laser driver through a first switch. A printing power reference holding capacitor and a beam detect power reference holding capacitor is selectively connected to the laser driver through a second switch that is controlled in tandem with the first switch. During each scan cycle, the output laser power is monitored and used to adjust one of the two holding capacitors based such that both the printing power and the beam detect power have a controlled reference.

Abstract: An apparatus for switching and controlling the intensity of a laser beam directed toward a beam detect sensor for an image forming device. A printing power reference signal and a beam detect power reference signal is selectively connected to a laser driver through a first switch. A printing power reference holding capacitor and a beam detect power reference holding capacitor is selectively connected to the laser driver through a second switch that is controlled in tandem with the first switch. During each scan cycle, the output laser power is monitored and used to adjust one of the two holding capacitors based such that both the printing power and the beam detect power have a controlled reference.

Abstract: A laser driver comprises a plurality of current sources, including at least one bias current source and at least two drive current sources. To control the laser driver, a set of operating states is defined where each operating state corresponds to a desired laser output power level and a ratio is defined that establishes a relationship between a first desired laser output and a second desired laser output. A calibration operation samples laser output power of the laser source for less than all of the operating states, computes adjustments to the current levels of the current sources based at least in part upon the ratio such that sampled laser power levels converge towards their corresponding desired laser output level. The current sources are adjusted to their corresponding computed current levels.

Abstract: A laser driver comprises a plurality of current sources, including at least one bias current source and at least two drive current sources. To control the laser driver, a set of operating states is defined where each operating state corresponds to a desired laser output power level and a ratio is defined that establishes a relationship between a first desired laser output and a second desired laser output. A calibration operation samples laser output power of the laser source for less than all of the operating states, computes adjustments to the current levels of the current sources based at least in part upon the ratio such that sampled laser power levels converge towards their corresponding desired laser output level. The current sources are adjusted to their corresponding computed current levels.

Abstract: Laser driver systems and methods are provided for controlling a laser driver coupled to a suitable laser source. The laser driver comprises a plurality of current sources, including at least one bias current source and at least two switched current sources. To control the laser driver, a laser power control signal is provided for each switched current source that corresponds to a desired laser output power. An output power error measure is defined based upon an error between a measured laser output power and the desired laser output power for each switched current source and a control system is characterized in which the output power error measures combine to change a magnitude of each of the switched current sources and the bias current source(s) such that the output power error measures converge over time.

Abstract: Laser driver systems and methods are provided for controlling a laser driver coupled to a suitable laser source. The laser driver comprises a plurality of current sources, including at least one bias current source and at least two switched current sources. To control the laser driver, a laser power control signal is provided for each switched current source that corresponds to a desired laser output power. An output power error measure is defined based upon an error between a measured laser output power and the desired laser output power for each switched current source and a control system is characterized in which the output power error measures combine to change a magnitude of each of the switched current sources and the bias current source(s) such that the output power error measures converge over time.

Abstract: An apparatus for switching and controlling the intensity of a laser beam directed toward a beam detect sensor for an image forming device. A printing power reference signal and a beam detect power reference signal is selectively connected to a laser driver through a first switch. A printing power reference holding capacitor and a beam detect power reference holding capacitor is selectively connected to the laser driver through a second switch that is controlled in tandem with the first switch. During each scan cycle, the output laser power is monitored and used to adjust one of the two holding capacitors based such that both the printing power and the beam detect power have a controlled reference.

Abstract: A method for improving the operation of an electrophotographic printer. The method includes providing an electrophotographic printer containing a laser scanning unit. A torsion oscillator for the laser scanning unit is enclosed in closed compartment. The closed compartment includes side walls having first and second side wall edges, a bottom wall attached on the first side wall edges, and a cover attached adjacent to the second side wall edges. The closed compartment is sufficient to reduce stray air currents from adjacent the torsion oscillator thereby improving the operation of the electrophotographic printer.

Abstract: A multi-layer printed circuit board (PCB) routes signal traces on internal signal layer(s) and includes power planes on the two outermost layers. The outer layers are maintained at the same non-ground voltage level, and are electrically connected by a series of vias that circumscribe signal traces on the internal layer(s). With a preferred maximum spacing of one-tenth the wavelength of electromagnetic energy generated by the signal traces, the vias, together with the outer power planes, contain electromagnetic energy within the PCB. One or more of the outer planes may include a second power plane area maintained at a different voltage. The two power plane areas are connected by decoupling capacitors, located proximate underlying signal traces that traverse the two power plane areas.

Abstract: An imaging apparatus includes a controller communicatively coupled to a first laser, a second laser, a scanning device and a light sensor. The controller is configured to perform actions including controlling the first laser, the second laser and the scanning device to simultaneously scan the first light beam and the second light beam across an image region of the photoconductive substrate over a plurality of scans to form a latent image on the photoconductive substrate; activating only the first laser outside the image region between first successive scans of the plurality of scans to sense with the light sensor the first light beam; and activating only the second laser outside the image region between second successive scans of the plurality of scans to sense with the light sensor the second light beam.

Abstract: A multi-layer printed circuit board (PCB) routes signal traces on internal signal layer(s) and includes power planes on the two outermost layers. The outer layers are maintained at the same non-ground voltage level, and are electrically connected by a series of vias that circumscribe signal traces on the internal layer(s). With a preferred maximum spacing of one-tenth the wavelength of electromagnetic energy generated by the signal traces, the vias, together with the outer power planes, contain electromagnetic energy within the PCB. One or more of the outer planes may include a second power plane area maintained at a different voltage. The two power plane areas are connected by decoupling capacitors, located proximate underlying signal traces that traverse the two power plane areas.

Abstract: Laser printers are designed assuming the actual laser operates at nominal values which are the average or central values of a large batch of such lasers. The nominal values are determined and stored in permanent memory. Similarly, the values of the laser actually in the printer are determined during manufacture and also stored in permanent memory. Data to the laser is adjusted to correlate the output called for by the data with the differences in response of the laser of the printer by determining the optical output called for by the data using the nominal values stored and then finding the power needed to achieve the same output using the actual values stored. This is particularly useful with extreme duty cycles.

Abstract: Laser printers are designed assuming the actual laser operates at nominal values which are the average or central values of a large batch of such lasers. The nominal values are determined and stored in permanent memory. Similarly, the values of the laser actually in the printer are determined during manufacture and also stored in permanent memory. Data to the laser is adjusted to correlate the output called for by the data with the differences in response of the laser of the printer by determining the optical output called for by the data using the nominal values stored and then finding the power needed to achieve the same output using the actual values stored. This is particularly useful with extreme duty cycles.